LayerTree2JSON

QGIS plugin which writes a JSON config file with layer information for the open QGIS 3 project.

LayerTree2JSON makes it easy to syncronize your QGIS 3 proyect with a web map viewer. It parses the Qgis project and writes a JSON config file with layer information. Additionally it can handle the upload using SFTP.

Notes:

• It doesn't create a web map for you so, you still have to code your map and use the produced JSON file from their, for example to make a Layer Switcher.
• Additionally you need to set up QGIS Server to produce the WMS tiles.
• WFS right now is not supported out of the box, but will be soon.

Installation

The plugin uses paramiko to upload the generated configuration files to a SFTP server. This Python library has some dependencies which can't be resolved easily on different operating systems, so for now you have to manually install paramiko:

1. Open console and go to qgis_installation_directory\apps\Python39\Scripts\ (or just OSGeo4W_installation_directoy on Windows)
2. Type: pip install paramiko
3. Install the plugin from QGIS

Configuration

Initially you have to add a new project clicking New button:

You have to fill out at least the field Project Name. On clicking OK some fields are filled out using default values. Opening up the configuration window again clicking Edit, you should edit the fields QGS file, QGS path, JSON path and JSON folder to your server settings:

There are 2 important directories to use a web map with QGIS Server:

1. Path to QGIS file used by QGIS Server: This path is formed using QGS path plus QGS file fields, for example: /home/me/newproject/newproject.qgs
2. Path to JSON file used by web map: This path is formed using JSON path plus JSON folder plus the QGS file plus .json, for example: /var/www/html/newproject/js/data/newproject.qgs.json

Note: For now the name of the QGS file has to be exactly the same as the local .qgs file you use for this project.

Test server connection

To test the server configuration, you have to fill out the field Server Host, which enables the buttons Show published project and Show published JSON file:

• Show published project opens a web browser with the URL build by Host plus Name, for example: https://mymapserver.com/newproject/. In this folder you should publish your web map.
• Show published JSON file opens a web browser with the URL build by Host plus JSON folder, for example: https://mymapserver.com/newproject/js/data/newproject.qgs.json

FTP upload

To use the full power of the plugin and upload your settings to the server you also have to fill out FTP User and FTP Password. Then you should test the settings clicking the button Test connection which shows you the success using QGIS notifications.

Use the plugin

The plugin does parse your active QGIS project and creates a JSON file with all your groups and layers. It reproduces the actual state of QGIS Layers Panel, so you should do the following preparations in order to get a nice result in your web map:

• Group, order and name your groups and layers as you would like to see them in your web map.
• Give your layer columns human friendly names via Layer > Properties > Attributes Form > Fields > Alias.
• The plugin takes the configuration of layer identification from the QGIS project properties. In order not to make some layers identifiable uncheck them from Project > Properties > Data Sources > Layer > Identifiable.
• The plugin takes the configuration which fields to show from QGIS layer properties. In order to hide fields from layer properties by changing their Widget Type to Hidden in Layer > Properties > Attributes Form > Fields.

Additionally there are some special characters which allow you to do the following:

• Prepend character @ to hide layers: This sets "hidden": true in JSON and could be used to tell the layer switcher to avoid showing a layer or group but render them by default.
• Prepend character ~ to hide the legend: This sets "showLegend": false in JSON could be used to avoid rendering the legend in layer switcher.
• Prepend character ¬ to load WMS layers directly: This sets "external": true in JSON. This option also looks up the layer source and writes the following parameters:
  • "wmsUrl": ''
  • "wmsLayers": ''
  • "wmsProjection": ''
• Prepend character ¡ to totally ignore layers for export.

Clicking OK starts the parser and saves the JSON file in the same folder of your .qgs file. By default is then opened in your default web browser:

If you would like to upload the produced JSON and the QGIS project file to a web server, you have to fill the related fields in project configuration and change to Mode Upload to server.

FAQ

After installing the plugin the following error message does show up: ModuleNotFoundError: No module named 'paramiko'

You have to install python library paramiko as explained in section Installation

After installing the plugin the following error message does show up: ModuleNotFoundError: No module named 'pysftp'

You are using an older version of the plugin and you have to install python library pysftp. Follow the steps explained in section Installation but substitute paramiko by pysftp.

When uploading a project including layer files QGIS gets blocked and I see something like that:

Static layer files (like .shp, .gpkg, etc.) can be huge and uploading these files per FTP to the server can take a while. As the upload happens in the same thread, QGIS can get blocked for a while. This message will disappear automatically once the upload is finished.